1. Field of the Invention
The present invention relates to a system for coloring an optical lens into a desired pattern (hereinafter referred to as an optical lens coloring system), and a method for coloring lenses.
2. Description of the Related Art
Spectacle or eyeglass lenses have come to be often worn and are used not only for the purpose of correcting visual acuity but also for the purpose of obtaining a particular cosmetic effect or medical effect (to protect the eves from ultraviolet rays, for example) in recent years, and, along with that, coloring of spectacle lenses has come to be actively conducted. Because gradation colored spectacle lenses have a highly desirable cosmetic effect, they account for a considerable percentage of colored spectacle lenses.
As methods for coloring spectacle lenses, there have been known (i) a method of fixing liquid having coloring capability after adhering on a base material lens by means of a soaking method, a spraying method or a spinning method (spinner method) (see JP-A-60-235101), (ii) a method of pasting a colored film on a spectacle lens to transfer coloring agent contained in the film to the spectacle lens (diffusion transferring method), and (iii) a method of coloring a spectacle lens by heating and sublimating organic pigment in a gaseous phase (see JP-B-35-1384).
The method (i) described above is a suitable method in coloring the whole surface of the lens uniformly and allows a colored spectacle lens whose thickness of a colored layer is uniform, whose color is uniform, whose color tone and concentration are constant, whose color does not fade and whose color tone does not change to be obtained. However, in implementing gradation coloring on spectacle lenses, the method (i) described above cannot be said to be a particularly preferable method for the following reasons.
It is necessary to adhere liquid having a tinting power to the spectacle lens (base material lens) in advance by soaking in order to implement gradation coloring because it is very difficult to implement gradation coloring in the desirable manner by application of a spraying or spinning method (spinner method) in adhering a coloring solution to a small object such as the spectacle lens. It thus becomes necessary to control the time for soaking the spectacle lens (base material lens) in the liquid per part of the lens. As a result, it takes a long time to color lenses in this manner and it is difficult to fabricate colored lenses efficiently.
Meanwhile, it is necessary to make a film gradation-colored by the method (i) described above and to transfer a coloring agent by pasting this film onto the spectacle lens in implementing gradation coloring on a spectacle lens according to method (ii) described above. However, it is difficult to paste the film precisely on the surface of a spectacle lens because the surface of the lens is curved. Therefore, method (ii) above, has had problems from the aspect of precision.
It is also very difficult to implement gradation coloring on a spectacle lens by the method (iii) described above.
It is therefore an object of the present invention to provide an optical lens coloring system for efficiently providing an optical lens or its base lens material, or, specifically, a spectacle lens or its base lens material, with a desired color pattern of a desirable color, e.g., letters, patterns, gradation coloring or the like, on the surface of the lens or base lens material.
It is also an object of the present invention to provide a method for coloring lenses having the above characteristics.